The present invention is directed to a method and system for preventing permanent deformation during use and storage, of encased expandites that constitute a thermodynamic working fluid for use in combination with a thermal fluid in a thermodynamic energy conversion system.
The use of such a working fluid in thermodynamic energy conversion systems is described in applicant's U.S. Pat. No. 4,214,449 entitled "Thermal Energy Conversion System Utilizing Expandites" and U.S. patent application Ser. No. 123,491 filed Mar. 10, 1980 entitled "Thermodynamic Energy Conversion System and Method, Utilizing a Thermodynamic Working Fluid of Encased Expandites," the disclosures of which are incorporated herein by reference thereto.
The thermodynamic working fluid is made up of thousands of encased expandites, each of which includes a mass having a flexible covering encasing the mass for enabling rapid heat transfer between the mass and the thermal fluid, for enabling the encased expandite to maintain its integrity as a separate object when submerged in the thermal fluid, and for enabling the volume of the encased expandite to change in accordance with the characteristic interdependent relationship between changes in the density, temperature and pressure of the mass when the encased expandite is submerged in the thermal fluid. Each of the flexible coverings has a maximum containing volume prior to becoming permanently deformed.
Many thermodynamic energy conversion systems operate at super atmospheric pressures, whereby the encased expandites are adapted for expanding to not more than the maximum containing volume of the covering when in use at a predetermined super atmospheric pressure and a predetermined temperature. If such encased expandites were to be exposed to atmospheric conditions of temperature and pressure they would become permanently deformed, as a result of the volume of the expandite mass increasing to exceed the maximum containing volume of the covering. Permanent deformation may include such as rupture of the covering or permanently stretching the covering to change its shape.